Control for elevator door



Jan. 23, 1968 M. w. ZELLER ET AI- 3,355,025

CONTROL FOR ELEVATOR DOOR Filed Oct. 5l, 1966 United States Patent Otice d Patentedv Jan. 23, l 68 3,365,025 CONTROL FOR ELEVATR DOOR Michael W. Zeller and .lack C. Van Derweil, Kansas City, Mo., assigners to Montgomery Elevator Company, a corporation of Delaware Filed Oct. 31, 1966, Ser. No. 590,695 16 Claims. (Cl. 187-52) ABSTRACT OF THE DISCLOSURE A multiple car elevator system of the nondispatching interval type having a control circuit which extends lthe terminal door open time period of individual cars when a car call is registered, indicating that a loa-d is to be transported to another floor. The door open time is extended only upon the iirst selection of a car call, and not for subsequent selections of a car call.

Specification This invention relates to an elevator system, and more particularly to apparatus for controlling an elevator door.

The eiectiveness yof an automatic elevator installation is directly related to the sophistication of the elevator door control. By controlling the door open time period, the flow of traffic into and out of the elevator car, and the relative spacing of multiple elevators in a hoistway can be controlled. When a plurality of elevator cars are to serve a number of landings, it has been thought necessary that the several control `circuits must interact to space the cars properly throughout the hoistway to serve eiciently all the landings. While many control circuits have been ldeveloped for this purpose, their complexity and cost often do not justify their use in simple elevator installations involving a small number of elevator cars, or a small number of landings.

lt has not previously been feasible to provide the advantages of a complex interacting multiple car elevator control in simple elevator installations, such as a group of elevators of the nondispatching interval type. In a nondispatching interval system, a car leaves a floor as soon as la call is registered by the car or hall call means, regardless of the expected tratiic flow. Thus, the interval between cars is not regulated, although heavy tra'ic throughout a building is best served by evenly spaced cars. It has been found that when cars leave the terminal promptly on registration of -a car call, they will tend to bunch up and travel through the hoistway in a group, often leaving the home station with a minimum load of passengers. By providing an extended door open time period, some of the advantages of dispatching type control systems can be realized in much simpler control systems. More passengers are allowed to enter before the car leaves. Each car therefore carries a larger load, and the interval between cars is increased. However, when there are no wating passengers at a home station, an elevator car should close its doors `after a short door open time period in order to be available to return to other floors on demand. These conflicting requirements are accomplished in a simple and effective manner by the door control disclosed herein, which is operative to extend the door open time only when 'a condition indicates a load is waiting to be transported from a home station to another floor.

One object of this invention is to provide an improved door control for an elevator system.

Another object of this invention is to provide an independent door control for each car in a multiple car elevator installation, which independent control provides some of the advantages of an interacting door control system, such as a dispatching interval type installation.

One feature of this invention is an elevator door control which extends the door open timing period when a condition occurs which indicates a load is to be transported to another floor. By extending, rather than maintaining or decreasing the door open time, a unique elevator operation is produced which has the advantages of more complex elevator control systems.

Another feature of this invention is the provision of an elevator control which extends the door open time at a terminal iioor when la car call is registered.

Yet another feature of this invention is the provision of an elevator door control which extends the door open time by the first occurrence of a particular condition, and not for subsequent occurrences of the same condition.

Further features and advantages of the invention will be apparent from the following speciication and from the drawings, in lwhich:

FIGURE l is a diagrammatic illustrati-on of a plurality of elevator cars whose door operation is controlled in accordance with the present invention; and

yFIGURE. 2 is a partly block and partly schematic diagram of the door control circuit for a single elevator car.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms, and it should be understood that the present disclosure is to be considered ias an exemplification of the principles of the invention, and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

In FIGURE l, a pair of elevator cars 1t) and '10 are ydiagrammatically illustrated in a typical elevator installation which may be controlled by the present invention. While only two cars have been illustrated, the invention may be used with more cars, if desired. For simplicity, corresponding `parts on the second car 10 will be identitied by the same reference numeral as those of the rst car I1t), followed by a prime.

Each elevator car is suspended by 'a cable 1v1 lwhich passes over a sheave 12 mounted to an elevator car driving motor 14. Each is secured to the floor ii-S lof an elevator penthouse. The opposite end of cable 11 passes back through an opening in iioor l15 and is attached to a counterweight 16. Motor d4 is connected to a suitable control circuit (not illustrated) which controls movement of the elevator car 1t) between the various floors it serves. At each iioor a hall call push button 18 is located for registering calls for elevator service. In add-ition, car call push buttons 19 are located within elevator car 10 to allow passengers to select the oor to which they wish to go.

As elevator car approaches and stops at a landing at which a call has been registered by either the hall call push buttons 18 or the car call push buttons 19, an elevator door 21 movably mounted to close a passage through the elevator car is opened by motive means, such as a bi-directional door operator motor DOM. The door 21, which may have multiple sections, may be connected to the bi-directional motor through any conventional door operating mechanism. Furthermore, a hoistway door (not illustrated) may be provided to cover a hoistway passage associated with each landing, through which a load enters and leaves the elevator car. The hoistway door may be coupled for movement with the elevator car door 21 by known mechanisms.

In accordance with applicants invention, the door 21 of each elevator car is controlled by the circuit illustrated in FIGURE 2. An identical circuit is provided for each car in the system. Although each door control circuit is independent of the other, they provide some of the advantages of an interconnected elevator control. More 3 particularly, the elevator door open time is extended when a floor call is registered at a home station by a passenger in the car. Hall call registration does not modify the door time operation. Thus, the door open time is extended to allow more passengers to enter and to space the cars through the hoistway only when a load is waiting to be transported from a home station to another iioor.

In FIGURE 2, only those circuits necessary for an understanding of the invention are shown. Turning now to FIGURE 2, energizing lines 24, are connected to a suitable source of electrical power (not illustrated) for energizing the control circuit. The bi-directional door operator motor DOM, when connected across power lines 24, 25 through either an open direction control circuit 27 or a close direction control circuit 28, rotates the motor in the proper `direction to open or close door 21. A normally open contact DO-l and a normally closed contact DO-Z of a door operator relay DO are respectively connected to the open direction circuit 27 and the close direction circuit 2S for connecting the source of power to the motor DOM through only one of the direction control circuits at a time.

Relay DO is energized by a conventional door control initiating and timing circuit 3G. Circuit 30 energizes relay DO, closing contact DO-l to cause the door operator motor DOM to open the car door. After a suitable time period, relay DO is dee ergized to cause contact DO-Z to close and apply closing direction power to the door motor. The basic circuit described above is typical of a simple, conventional non-dispatching interval type control, in which the basic timing period needed to open and thereafter close the elevator door is constant for each floor. Other suitable apparatus (not illustrated), such as safety edges, may be associated with the elevator door circuit in a known manner. Such apparatus as a safety edge is effective at all floors to modify the basic timing period temporarily when a safety hazard is sensed.

In accordance with the invention, remaining circuitry illustrated in FIGURE 2 modifies the basic door control -circuit described above. This circuitry extends the door open time, as from four to fourteen seconds, only at terminal or home station landings, such as the bottom floor in a building, once the elevator car begins a loading sequence.

The extended door open time occurs when a signal indicates a load is to be transported to another door. The signal could, for example, be formed by a dual beam photocell circuit which indicates when a load enters through the elevator door passageway. Desirably, however, the signal is formed by apparatus already existing for other purposes. In the system to be described, the first operation of a car call push button 19 is used to generate this signal.

When a passenger enters the elevator car and presses oneof the car call buttons i9, a signal is formed by the change in the voltage level at a contact 31 on the car call push buttons. This change in voltage level momentarily energizes a relay DS, causing a normally open relay contact DS-l to close. The remaining contacts on push buttons i9 operate to car call relay coils (not illustrated) connected in a suitable manner with the control circuit for the elevator driving motors 14.

The momentary closure of contact DS-l energizes relay 12X which is maintained energized through normally open holding contact 12X-1 only when a segment 33, corresponding to a terminal floor, is in contact with a movable brush 34 Whose position corresponds with the position of the elevator car in the hoistway. The movable brush 34 may be located on a brush carriage (not illustrated) which is engaged through a suitable connection to the shaft of the elevator motor14, in a manner conventional for floor selectors located in elevator penthouses. Similarly, the connection between energizing line 25 and relay lZX may be made through a bi-stable memory element in a static elevator car position indicator. Other arrangements can be used to form the electrical signal at only those floors where heavy loads are expected.

Simultaneous with the closing of self-holding contact lZX-, a second normally open contact 1ZX-2 on relay lZX is closed to shunt the door control circuit 34) through a normally closed contact TlZX-l. This shunt path directly connects relay DO to energizing line 25, thereby maintaining contact DO-1 closed to hold therdoor in its open position. A time delay relay TlZX is energized at the same time as relay 12X, and begins a timing interval of predetermined duration which is longer than the time period of the door control circuit 30, as fourteen seconds. The contacts of timer TlZX are actuated only after the predetermined time interval is expired. Thus, normally closed Contact TlZX-l does not open until after fourteen seconds, and thereafter remains open While relay TlZX remains energized. Thus seconds after the door 21 was originally opened by the closure of contact IDO-1, the normal door control circuit 39 will open in a normal manner, but relay DO will remain energized through contacts 1ZX-2 and T1ZX-1. After fourteen seconds elapses, timer TIZX times out, its normally closed contact T1ZX1 opening to deenergize relay DO and close the door 21.

As previously mentioned, contact TlZX-l remains open While relay TlZX is energized. Although another passenger may enter the elevator car and depress a push button i9, thereby energizing relay DS to momentarily close contact DS-l, the extended door open time period will not again be extended since relay TZX is at this time already energized. When the elevator car leaves the terminal floor, brush 34 will move olf segment 33, deenergizing time delay relay TlZX, causing its contact TlZX-l to close. Therefore, the extended door open timing period occurs only once for any particular terminal floor.

After timer TlZX has timed out and the door begins to close, relay DO may still be energized through the normal door control circuit 3i). Therefore, conventional door reopening operations, such as door safety edges or open door push buttons, may be actuated to energize relay DO and open the door temporarily in accordanceV with the particular safety or control function being performed. The applicants invention in no way interferes with the operation of such additional door reopen circuits as may be incorporated in door control circuit 30.

Once the elevator car is in a loading sequence at a home station, the extended door open timing period is effective to increase the amount of time the car is located at the terminal floor. This allows suiiicient time for waiting passengers to enter the car, preventing the car from leaving a home station with a minimum load of passengers, and further prevents the elevator car from sooner leaving the terminal landing, elfectively preventing the elevator cars from -bunching up and traveling through theV hoistway in a group. Thus, certain of the advantages of a dispatching interval type system are realized in a much simpler elevator system in which travel of a plurality of elevator cars is not interrelated. Applicants invention has the further advantage that should no passengers depress a car call push button 19, the elevator door 21 will close after the basic four second timing period expires. This allows the elevator car to be available to travel immediately to other doors on demand. While the extended door open time circuit is desirable in an elevator system having multiple elevator cars, it will 'be apparent that certain of the advantages, such as extending the door open time only if passengers at certain floors begin loading when the elevator car stops at that door, are advantageous in a single car elevator system.

We claim: Y

1. In an elevator system including an elevator car serving a plurality of floors, apparatus for controlling the door of the elevator car, comprising: motive means for opening and closing said door; signalling means responsive to a condition which indicates a load is to be transported to sesame 5 another oor for producing a signal; and timer means for controlling said motive means to maintain said door substantially open for a basic door open timing period, said timer means being responsive to said signal to extend said basic door open timing period for a iixed timing period independent of the time period of said signal.

2. The door controlling apparatus of claim l in an elevator system further including hall call means located at each floor and car call means located within the car for selecting a door the car is to serve, wherein the condition which indicates a load is to be transported is the operation of a car call means.

3. The apparatus of claim l wherein said timer means is operative to extend the timing period only when said elevator car is adjacent certain iloors corresponding to at least one but less than all of said doors.

4. The apparatus of claim 3 wherein said timer means includes lirst contact means completing an electrical path only when said car is adjacent said certain floor, second contact means completing an electrical path only when actuated -by said signal, a source of power, switching means Operative when connected to said power source for extending the timing period, and means connecting said first contact means, said second contact means, and said switching means in series across said power source.

5. In an elevator system of the nondispatching interval type having a plurality of elevator cars serving at least one terminal oor and at least one intermediate door, including motive means for opening and closing the elevator doors, and means controlling the motive means during a basic timing period which is the same at both terminal and intermediate floors to open and thereafter close the doors, the improvement comprising: signalling means responsive to a condition which indicates a load is to be transported to another door for producing a signal; means or extending the basic timing period by a iixed length of time; and means responsive to said signal for actuating said extending means to extend by said fixed length of time the basic timing period of the car at which the condition occurred only when the car is adjacent a terminal iloor, thereby extending the door open time when a loading sequence begins at a terminal door.

6. rihe apparatus of claim 5 further including hall call means located at each floor and car call means located within each car for selecting the iloors the cars are to serve, wherein the condition which indicates a load is to be transported comprises the selection of a car call means.

'7. The apparatus of claim 5 wherein said extending means includes timing means which completes a iirst circuit for an extended time period longer than said basic timing period, said rst circuit being in shunt with said motive controlling means to extend the basic timing period when said timing means is activated, said signalling means producing a momentary signal, means forming a holding circuit for maintaining said timing means activated after the momentary signal expires, door level switching means having a second circuit corresponding to each door and means completing the corresponding second circuit when the car is adjacent that door, and means connecting the second circuit for the terminal floor in series with the timing means and the holding circuit to activate said timing means only when the car is adjacent the terminal door.

8. ln an elevator system including an elevator car serving a plurality of doors, apparatus for controlling the door of the elevator car, comprising: motive means for opening and closing said door; hall call means located at each door the car is to serve; signaling means responsive -to the operation of a car call means as representative of a condition which indicates a load is to be transported to another floor for producing a signal; and timer means for controlling said motive means to maintain said door substantially open for a basic door open timing period, said timer means being responsive to said signal to extend said basic door opening timing period, including means for preventing the extended door open timing period from being further extended by the subsequent operation of said car call means.

9. The apparatus of claim 8 wherein said timer means is operative to extend the timing period only when said elevator car is adjacent certain iioors corresponding to at least one but less than all of said floors, said timer means including -rst contact means completing an electrical path only when said car is adjacent said certain doors, second contact means completing an electrical path only when actuated by said signal, a source of power, switching means operative when connected to said power source vfor extending the timing period only once while continually connected to said power source, means connecting said iirst contact means, said second contact means, and said switching means in series across said power source, and normally open holding means shunting said second Contact means and responsive to the first occurrence of said condition for completing a shunt electrical path as long as said rst contact means continually completes its electrical path.

itl. In an elevator system of the nondispatching interval type having a plurality of elevator cars serving at least one terminal door and at least one intermediate floor, including motive means for opening and closing the elevator doors, and means controlling the motive means during a basic timing period which is the same at both terminal and intermediate floors to open and thereafter close the doors, the improvement comprising: signaling means responsive to a condition which indicates a load is to be transported to another door for producing a signal; means responsive to said signal for extending the basic timing period of the car at which the condition occurred only when the car is adjacent a terminal floor, thereby extending the door open time when a loading sequence begins at a terminal floor; and means for preventing the extended timing period from being extended by the subsequent occurrence of the condition at the same car at which the condition originally occurred.

References Cited UNITED STATES PATENTS 3,301,350 1/1967 Hallene 187-52 RICHARD E. AEGERTER, Primary Examiner. EVON C. BLUNK, Examiner.

H. C. HORNSBY, Assistant Examiner. 

